Insects are a primary source of nutrients and energy for a large number of animals. Wild insectivores typically feed on a wide variety of invertebrates, such as insects, spiders, isopods, ticks, millipedes, centipedes, and other arthropods. Since wild insectivores eat the food that they happen across in nature, there is high variability in the type of wild insect that becomes an insectivore's meal. Additionally, each wild insect likely differs significantly in nutrient composition from other insects the wild insectivore may consume. As such, the wild insectivore not only eats a wide variety of wild insects, but each wild insect consumed possesses a broad nutrient profile. Wild insectivores thus eat a broad, varied diet which includes a full nutrient spectrum that supports a lengthy, healthy life.
For animals kept in captivity, such as reptiles, birds, mammals, fish and invertebrates in zoos and homes, feeder insects replace wild insects as the main and most important source of food and nutrients. Feeder insects are typically purchased by the captive insectivore owner, whether a commercial establishment or a hobbyist pet owner, in bulk and often become the exclusive component of the diet of the insectivore. For example, most pet owners have only three to four different types of feeder insects available to purchase from a local pet store; crickets, mealworms, superworms, and waxworms are typically the primary feeder insects available. A pet owner may purchase all four, or, for simplicity, the pet owner may purchase only a single feeder insect type and feed that to the pet exclusively. The captive insectivore is thus exposed to a very limited diet of feeder insects.
Compounding the problems associated with the consumption of only a few types of feeder insects by a captive insectivore, the feeder insects themselves provide a very limited nutrient profile. The vast majority of feeder insects are grown by large commercial grower operations, in which feeder insects have diets designed to enhance growth rather than nutrition. While such feeder insects may be good sources of nutrients such as protein, amino acids, trace minerals, and most B-vitamins, many other important nutrients are lacking, such as vitamin E, carotenoids, essentially fatty acids, vitamin A, and other nutrients beneficial for the health of the feeder insect.
Because commercial growers grow feeder insects during a growth phase of the feeder insect life cycle and ship the feeder insects during a maintenance phase of the life cycle, commercial growers focus on developing the size and weight of the feeder insect. While insect species vary in the length of their growth phases, most commercially-grown feeder insects have a growth phase ranging between 3 days to 30 days. For instance, small crickets are grown for about 3 to about 5 days, while adult crickets have growth phases lasting for approximately 25 to approximately 30 days. Mealworms and superworms have growth phases lasting for approximately 10 to approximately 30 days. During the growth phase, the diet fed to the feeder insect is directed toward improving the raw growth of the feeder insect, rather than the nutritional quality of the feeder insect as a food source for insectivores. Following growth, during the maintenance phase of the life cycle of the feeder insects, the feeder insects are shipped to stores, where feeder insects will sit for approximately a few days to a few weeks before being purchased by a consumer. After purchase, feeder insects will generally be kept at the consumer's house for as little as 24 hours to as long as one to six weeks until being fed to an insectivore. Some feeder insects, such as mealworms, can be refrigerated to increase the life span. The feeder insects purchased by the hobbyist or zoo lack many nutrients. When the zoo or hobbyist is ready to feed the captive insectivore, in order to provide the insectivore with a complete spectrum of nutrients, the zoo or hobbyist must supplement feeder insects with nutrients before feeding the feeder insects to insectivores.
Currently, zoos and hobbyists fortify feeder insects with nutritional content in one of two ways. One method, known as “gut loading,” involves forcibly feeding a diet high in a few nutrients and soon thereafter feeding the feeder insect to the insectivore. In this manner, the feeder insect's gut essentially becomes a short-term delivery capsule for retaining consumed nutrients and providing the nutrients in the feeder insect's diet directly to the insectivore.
Many of the nutrients are passed through the digestive system of the feeder insect before the feeder insect is consumed, however, so to provide nutrients to the insectivore in this manner, the feeder insect must be fed a gut-loaded diet that is extremely high in nutrients. Unfortunately, despite the fact that the gut-loading diet is fed after the growth phase and during the maintenance phase of the feeder insect, the gut-loading diet is not a maintenance diet; gut-loading diets can be toxic to feeder insects due to the high concentrations of nutrients. Gut-loaded insects typically live for only approximately 96 hours following introduction of a gut-loading diet. Immediately following introduction of the gut-loading diet, the feeder insect begins to eliminate many of the nutrients in the diet. Gut-loaded nutrients are absorbed by the gut-loaded feeder insect during the first 36 to 48 hours following introduction of the gut-loading diet, which is the approximate amount of time required for the insect to fill the entire gastrointestinal tract with the newly-consumed food. The nutrients level may plateau for a period of time or begin to decline as the feeder insect consumes less food because the feeder insect begins to lose vitality or because of the poor palatability of the diet.
In addition to the very small window of time that a gut-loaded feeder insect is useful as food, the gut-loading diet presents other problems. For instance, because feeder insects die soon after gut-loading, gut-loaded feeder insects must be separated from feeder insects being fed a maintenance diet, which can be burdensome for zoos and hobbyists. Moreover, some feeder insects will not accept gut-loaded diets at all; waxworms and large-size soldier fly larvae stop eating following the growth phase. Further, the gut and gut contents of many feeder insects are only between approximately 4% and approximately 8% by weight of the feeder insect, so the feeder insect can only carry nutrients in a very small proportion of the total body mass of the feeder insect. In crickets, the gut and gut contents are approximately 4.5% to approximately 6% of the total body weight. Further still, few hobbyists have access to raw materials or the knowledge to produce gut-loading diets, and because proper gut-loading can be very difficult to administer when using a commercially-purchased gut-loading diet, the hobbyist can inaccurately dose the feeder insect and improperly feed the insectivore. Yet still further, some nutrients depress the palatability of the feeder insect, thus reducing the likelihood that the insectivore will consume the feeder insect and the nutrients its gut contains. For these reasons and more, properly supplementing, maintaining, and using feeder insects is incredibly difficult for insectivore owners.
Another method employed by zoos and hobbyists is called “dusting.” In the dusting method, nutrients are desiccated, combined, and then dusted or applied to the exterior of the feeder insects prior to feeding to the insectivore. While dusted nutrients do adhere to the exterior of some feeder insects, such as crickets, nutrients do not adhere well to the exterior of other feeder insects, such as mealworms, superworms, and waxworms. Moreover, all feeder insects groom themselves, and as such, will quickly begin to groom off any nutrients that have adhered, thus limiting the amount of time in which the nutrients are available to be fed to the insectivore. Crickets, for example, are known to dust the nutrients off within 1-2 minutes of application. Further, some nutrients are not readily amenable to being desiccated, and others have unpleasant flavors that reduce insectivore consumption. Still further, because of the difficulty in dusting all feeder insects consistently, and because of the problems associated with adherence and grooming, it is very difficult to accurately and consistently dust a feeder insect such that the feeder insect will carry an optimum level of nutrients when consumed by the insectivore.
There is very little information known about how insects process nutrients. It is not well understood how particular levels and combinations of nutrients interact in insects, are absorbed and stored, are digested and processed, or are eliminated by insects. For these problems and others, many pet insectivores suffer from a host of nutritional deficiencies.